This invention relates generally to radio frequency (RF) receivers and more particularly concerns RF receivers capable of receiving a plurality of different codes at a plurality of different frequencies.
Transmitters and receivers are becoming more and more widely used to control the operation of an ever increasing amount of devices and systems. Originally used for military applications and large-scale broadcasting needs, transmitters and receivers have evolved to such an extent that they are now being used in applications as personal as medical implants. In fact it is becoming almost impossible to go a day without using a device that operates via a transmitter and receiver. For example, our cars, garages, shutters, etc. are all offering control via transmitters and receivers. Every day new systems are being designed to take advantage of the mobility transmitters and receivers offer and the ease with which they make even the most tedious of tasks.
As such, there is currently available a wide variety of transmitters and receivers made by numerous manufacturers. Typically each manufacturer's transmitters and/or receivers operate via codes and frequencies unique to that individual manufacturer. Unfortunately, like all electronics, transmitters and receivers can break and/or become damaged. When this happens, it often becomes necessary to purchase replacement parts. However, since most manufacturers build their products to operate via codes and frequencies unique to themselves, consumers are stuck having to buy replacement parts from the original manufacturer. This limits competition and can often make the cost of the replacement part much higher then it would be if other suppliers were available. In some industries, universal transmitters are offered for sale which can be used on a variety of products made by a variety of manufacturers. For example, in the garage door operator industry, there are several universal transmitters that are capable of operating a variety of door receivers.
Although several universal transmitters are available and help increase competition and/or the number of available suppliers of replacement parts, there are no such alternatives for receivers. If a receiver breaks or is damaged to the extent it needs to be replaced, the user would have to go and purchase an entirely new system or buy a replacement unit from the same manufacturer of his or her old receiver. This may not always be convenient and could be cost prohibitive.
Receivers that are capable of receiving a plurality of different codes at a plurality of different frequencies would not be limited to use as replacement parts. Indeed many service personnel who both install and repair movable barrier operators would prefer carrying such a receiver because it would reduce the need for having several different brands of receivers in their inventory. In addition, it would reduce the number of receivers the service personnel would need to learn how to operate. The mere fact they would be able to buy a larger quantity of receivers from one manufacturer may also allow them a reduced price per unit or price break of some type.
Accordingly, there is a need for a receiver capable of receiving a plurality of different codes at a plurality of different frequencies. There is also a need for a sensitive receiver that can offer these capabilities at relatively low current. There is a further need for a receiver that can offer these capabilities without amplifying unwanted signals resulting from switching in a high gain RF amplifier circuit.